The present invention relates to a high-density electric connector called as a BGA connector to be connected to a board through solder balls arranged in a grid-like array.
With a recent advance of an electronic apparatus, such as a computer, toward a high-density and miniaturization unit, a surface-mounting high-density connector called a BGA connector ha been developed in which solder balls are arranged at the connection sections of respective terminals to be connected to a board and such solder balls are a ranged as a grid-like array on the connector housing. The BGA connector is placed on contact pads arranged on a board surface and each solder ball is partially melted by heating and bonded to the corresponding contact pad on the board. The distance between th mutually adjacent solder balls is very narrow and a larger number of solder balls can be provided on the board in a limited range.
In the BGA connector, a large number of slots extend through the bottom wall of an insulating housing and a terminal is received in each lot. Normally, respective projections are provided in a coaxially opposed state, on an opposite wall of each slot. The respective terminal has its retaining section forced into the slot at an area between the opposite projections and is held in the slot, while the retaining section is pushed by the opposed projections from both sides. A contact section contacting with the terminal of the associated connector is projected from a mating surface mated to the associated connector and a connection section is placed in the corresponding opening on an attaching surface side attached to a printed circuit board and a solder ball is attached to the connection section. By simply pressing the respective terminal into the slot at an area between the opposite projections, the terminal can be readily attached to the housing.
In the case where a compact and high-density connector is formed for use in an IC package, such as a CPU, the dimensions of the housing, such as the wall thickness and height, are restricted to very small values and a force by which such a terminal is retained in the housing produces a greater stress in the housing. Such a greater stress acting upon the housing provides a cause for a crack. In particular where the connector is soldered to a printed circuit board, etc., by a reflow soldering, there is produced a cause for thermal deformation.
It is accordingly the object of the present invention is to provide a very simple and inexpensive electric connector which can positively retain respective terminals in associated slots in the housing and prevent any deformation of the housing.
In order to achieve the above-mentioned object of the present invention, there is provided an electric connector having an insulating housing and a plurality of terminals in the insulating housing, the housing receiving respective terminals and having a plurality of slots with a plurality of projections formed in a staggered fashion on mutually opposed surfaces, the terminal having a retaining section against which these projections abut and a projection abutting against one of the opposed wall surfaces, in which the projection on the other surface supports a terminal urging force to retain the terminal in place in the slot.
According to the electric connector, projections are projected in an offset fashion from the opposed surfaces in the slot and, when being abutted against the retaining section of the terminal, these projections impart no greater stress to the housing and, further, a projection on the terminal together with the above-mentioned projections in the slot, positively supports the terminal relative to the housing.
The housing has a mating surface mated to an associated connector and housing a terminal insertion inlet opened at the respective slot, the projection on the terminal is formed on the retaining section and a distance from a forward end of the retaining section to the projection of the terminal is preferably so formed as to be made longer than a distance between the mating plane and the projection on a side spaced apart from the mating plane. When, in this case, the forward end of the terminal engages the projection on a side spaced apart from the mating surface, since the projection is arranged outside the slot, the projection on the terminal is smoothly inserted without any intervention when the retaining section of the terminal is inserted between the opposed projections in the slot. Further the terminal preferably has a connection section externally exposed from the slot and on which the solder ball is mounted.
The projection can provide a contact making contact with the plate-like terminal when it is inserted in the slot. In this case, it is possible to provide a terminal of a simple structure which positively engages the plate-like terminal of a mating connector through the rotation moment of the two projection.